CN111785195A - Driving method of pixel circuit, compensation device and display equipment - Google Patents

Driving method of pixel circuit, compensation device and display equipment Download PDF

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Publication number
CN111785195A
CN111785195A CN201910273161.0A CN201910273161A CN111785195A CN 111785195 A CN111785195 A CN 111785195A CN 201910273161 A CN201910273161 A CN 201910273161A CN 111785195 A CN111785195 A CN 111785195A
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China
Prior art keywords
circuit
voltage
driving
sensing
signal line
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CN201910273161.0A
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Chinese (zh)
Inventor
孟松
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BOE Technology Group Co Ltd
Hefei Xinsheng Optoelectronics Technology Co Ltd
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BOE Technology Group Co Ltd
Hefei Xinsheng Optoelectronics Technology Co Ltd
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Priority to CN201910273161.0A priority Critical patent/CN111785195A/en
Publication of CN111785195A publication Critical patent/CN111785195A/en
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    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/006Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3275Details of drivers for data electrodes
    • G09G3/3291Details of drivers for data electrodes in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

A driving method of a pixel circuit, a compensation device and a display device are provided. In a blanking stage, writing a first detection data voltage into a control end of a driving circuit to enable the driving circuit to be conducted, and detecting a first sensing voltage on a sensing signal line after the sensing signal line is charged for a first time through the driving circuit; writing a second detection data voltage into the control end of the driving circuit to enable the driving circuit to be conducted, and detecting the second sensing voltage on the sensing signal line after the sensing signal line is charged for a second time through the driving circuit, wherein the first detection data voltage is different from the second detection data voltage; and calculating characteristic parameters of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time and the second time. In the display phase, the display data voltage applied to the driving circuit is compensated based on the characteristic parameter.

Description

Driving method of pixel circuit, compensation device and display equipment
Technical Field
The embodiment of the disclosure relates to a driving method of a pixel circuit, a compensation device and a display device.
Background
Compared with the conventional liquid crystal display panel, an Organic Light-Emitting Diode (OLED) display panel has the advantages of faster response speed, higher contrast ratio, wider viewing angle, lower power consumption, and the like, and has been increasingly applied to high-performance display.
The pixel circuits in the OLED display panel generally adopt a Matrix driving method, and the driving method of the pixel circuits is divided into Active Matrix (AM) driving and Passive Matrix (PM) driving according to whether a switch element is introduced into each pixel unit. Although the PMOLED has a simple process and a low cost, the PMOLED cannot meet the requirements of high-resolution large-size display due to the defects of cross-talk, high power consumption, low service life and the like. In contrast, the AMOLED integrates a set of thin film transistors and a storage capacitor in a pixel circuit of each pixel unit, and the current flowing through the OLED is controlled by driving and controlling the set of thin film transistors and the storage capacitor, so that the OLED emits light as required. Compared with PMOLED, the AMOLED has the advantages of small driving current, low power consumption and longer service life, and can meet the large-size display requirements of high resolution and multi-gray scale. Meanwhile, the AMOLED has obvious advantages in the aspects of visual angle, color reduction, power consumption, response time and the like, and is suitable for display devices with high information content and high resolution.
Disclosure of Invention
At least one embodiment of the present disclosure provides a driving method of a pixel circuit, wherein the pixel circuit includes a driving circuit, and the driving circuit includes a control terminal, a first terminal and a second terminal, the first terminal of the driving circuit is configured to be electrically connected to a sensing signal line and a light emitting element, and the second terminal of the driving circuit is configured to receive a power supply voltage. The driving method comprises a blanking period and a display period, wherein in the blanking period, a first detection data voltage is written into the control end of the driving circuit to enable the driving circuit to be conducted, after the sensing signal line is charged for a first time through the driving circuit, a first sensing voltage on the sensing signal line is detected, a second detection data voltage is written into the control end of the driving circuit to enable the driving circuit to be conducted, detecting a second sensing voltage on the sensing signal line after charging the sensing signal line for a second time by the driving circuit, the first detection data voltage being different from the second detection data voltage, calculating a characteristic parameter of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time and the second time; and compensating the display data voltage applied to the driving circuit based on the characteristic parameter in the display phase.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, the pixel circuit further includes a data writing circuit electrically connected to a control terminal of the driving circuit, and the blanking phase includes a first detected data writing sub-phase, a first charging sub-phase, a first detecting sub-phase, a second detected data writing sub-phase, a second charging sub-phase, and a second detecting sub-phase. The driving method further includes: in the first detection data writing sub-stage, controlling the data writing circuit to be conducted, and writing the first detection data voltage into the control end of the driving circuit through the data writing circuit; in the first charging sub-phase, the data writing circuit is controlled to be switched off, and the sensing signal line is charged for the first time through the driving circuit under the control of the first detection data voltage; in the first detection sub-phase, controlling the data writing circuit to be disconnected, and detecting the first sensing voltage on the sensing signal line after charging the sensing signal line for the first time; in the second detection data writing sub-stage, controlling the data writing circuit to be conducted, and writing the second detection data voltage into the control end of the driving circuit through the data writing circuit; in the second charging sub-phase, the data writing circuit is controlled to be switched off, and the sensing signal line is charged for the second time through the driving circuit under the control of the second detection data voltage; and in the second detection sub-phase, the data writing circuit is controlled to be disconnected, and the second sensing voltage on the sensing signal line is detected after the sensing signal line is charged for the second time.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, the pixel circuit further includes a sensing circuit, a first end of the sensing circuit is electrically connected to the sensing signal line, and a second end of the sensing circuit is electrically connected to the first end of the driving circuit and the light emitting element. In the first detection data writing sub-phase, the sensing circuit is controlled to be conducted, and a first reference voltage is written into the first end of the driving circuit through the sensing circuit; in the first charging sub-phase, controlling the sensing circuit to be conducted so as to charge the sensing signal line for the first time; in the first detection sub-phase, after the sensing signal line is charged for the first time, the sensing circuit is controlled to be closed, and the first sensing voltage on the sensing signal line is detected; in the second detection data writing sub-phase, controlling the sensing circuit to be conducted, and writing a second reference voltage into the first end of the driving circuit through the sensing circuit; in the second charging sub-phase, the sensing circuit is controlled to be conducted so as to charge the sensing signal line for the second time; and in the second detection sub-phase, after the sensing signal line is charged for the second time, the sensing circuit is controlled to be closed, and the second sensing voltage on the sensing signal line is detected.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, the pixel circuit further includes a storage circuit, a first terminal and a second terminal of the storage circuit are electrically connected to the control terminal and the first terminal of the driving circuit, respectively, and the storage circuit is configured to store the first detected data voltage and the second detected data voltage written by the data writing circuit.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, in the first charging sub-phase, a potential difference value between a control terminal and a first terminal of the driving circuit is kept unchanged; in the second charging sub-phase, the potential difference value between the control terminal and the first terminal of the driving circuit is kept unchanged.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, the first time is the same as the second time.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, the driving circuit includes a driving transistor, the characteristic parameter includes a process constant and a threshold voltage of the driving transistor, and the threshold voltage is obtained by the following calculation formula:
wherein Vth is a threshold voltage of the driving transistor, Vt1 is the first detection data voltage, Vt2 is the second detection data voltage, V1 is the first sensing voltage, V2 is the second sensing voltage, Vref1 is the first reference voltage, Vref2 is the second reference voltage, S1 is the first time, and S2 is the second time, and the process constant is obtained by the following calculation formula:
wherein K is a process constant of the driving transistor, and C is a capacitance value of a capacitor connected to the sensing signal line.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, the first detection data voltage, the first reference voltage, and the threshold voltage of the driving transistor satisfy the following relational expression: vt1-Vref1 is more than or equal to Vth, and the second detection data voltage, the second reference voltage and the threshold voltage of the driving transistor satisfy the following relation: vt2-Vref2 is equal to or greater than Vth.
For example, in a driving method of a pixel circuit provided in at least one embodiment of the present disclosure, compensating the display data voltage applied to the driving circuit based on the characteristic parameter includes: obtaining a display brightness value according to the display gray scale; and obtaining compensated data voltage corresponding to the display gray scale according to the characteristic parameters and the display brightness value, wherein the compensated data voltage is used as the display data voltage for the driving circuit to perform display operation.
At least one embodiment of the present disclosure provides a compensation apparatus including a data driving circuit, a voltage detection circuit, a calculation circuit, and a compensation circuit, wherein the compensation apparatus is electrically connected to a pixel circuit, the pixel circuit includes a driving circuit, and the driving circuit includes a control terminal, a first terminal, and a second terminal, the first terminal of the driving circuit is configured to be electrically connected to a sensing signal line and a light emitting element, the second terminal of the driving circuit is configured to receive a power supply voltage, and each frame time includes a blanking phase and a display phase. The data driving circuit is configured to write a first detection data voltage and a second detection data voltage to the control terminal of the driving circuit in sequence in the blanking period; the voltage detection circuit is configured to, during the blanking phase: detecting a first sensing voltage on the sensing signal line after charging the sensing signal line for a first time by the driving circuit under the control of the first detection data voltage, and detecting a second sensing voltage on the sensing signal line after charging the sensing signal line for a second time by the driving circuit under the control of the second detection data voltage; the calculation circuit is configured to calculate a characteristic parameter of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time, and the second time in the blanking period; the compensation circuit is configured to compensate the display data voltage applied to the driving circuit based on the characteristic parameter during the display phase.
At least one embodiment of the present disclosure provides a display device including the compensation apparatus according to any one of the embodiments of the present disclosure.
For example, at least one embodiment of the present disclosure provides a display device further including a display panel, where the display panel includes a plurality of pixel units, each of the pixel units includes the pixel circuit, and the compensation device is configured to compensate for a driving circuit of the display panel.
For example, in a display device provided in at least one embodiment of the present disclosure, the pixel circuit further includes a data writing circuit including a data writing transistor, a storage circuit including a storage capacitor, and a sensing circuit including a sensing transistor, the driving circuit including a driving transistor, a first electrode of the data writing transistor being electrically connected to a data line, a control electrode of the data writing transistor being electrically connected to a gate line, a second electrode of the data writing transistor being electrically connected to the first electrode of the storage capacitor and the control electrode of the driving transistor, a second electrode of the storage capacitor being electrically connected to the first electrode of the driving transistor, a second electrode of the driving transistor being electrically connected to a power supply voltage terminal to receive a power supply voltage, and the first electrode of the driving transistor being further electrically connected to a light emitting element and the first electrode of the sensing transistor, the second pole of the sensing transistor is electrically connected with the sensing signal line, and the control pole of the sensing transistor is electrically connected with the sensing control line.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description relate only to some embodiments of the present disclosure and are not limiting to the present disclosure.
Fig. 1 is a flowchart of a driving method of a pixel circuit according to some embodiments of the present disclosure;
fig. 2 is a schematic diagram of a pixel circuit according to some embodiments of the present disclosure;
FIG. 3 is a signal timing diagram of the pixel circuit shown in FIG. 2; and
fig. 4 is a schematic block diagram of a compensation device according to some embodiments of the present disclosure.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described below clearly and completely with reference to the accompanying drawings of the embodiments of the present disclosure. It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the disclosure.
Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
To maintain the following description of the embodiments of the present disclosure clear and concise, a detailed description of some known functions and components have been omitted from the present disclosure.
The basic pixel circuit used in an AMOLED display device is typically a 2T1C pixel circuit, i.e., two Thin Film Transistors (TFTs) and one storage capacitor are used to implement the basic function of driving the OLED to emit light. Due to factors such as manufacturing processes and temperature variations, the threshold voltages of the driving transistors in the respective pixel circuits may vary and may generate a drift phenomenon, thereby causing non-uniformity of the luminance of the display screen. Therefore, in order to achieve a good display effect, it is necessary to detect and compensate for the threshold voltage of each driving transistor.
In detecting the threshold voltage of the driving transistor, the driving transistor is generally charged to, for example, a detection circuit until the driving transistor is turned off, and the threshold voltage of the driving transistor is calculated from a voltage value acquired by the detection circuit to compensate. However, in the process of charging the detection circuit, as time increases, the voltage of one electrode (for example, the source electrode) electrically connected to the detection circuit of the driving transistor increases, and the gate voltage of the driving transistor remains unchanged, so that the current output by the driving transistor decreases continuously, and the charging speed of the detection circuit also decreases relatively, which results in a long required charging time.
In addition, since the difference between the threshold voltages of the driving transistors of the pixel circuits in the display device is large, in order to ensure that the driving transistors of the pixel circuits of the display device can be turned on during the detection process, the data voltage with a large amplitude needs to be uniformly applied during the detection. Correspondingly, the voltage amplitude of the electrode electrically connected with the detection circuit after the driving transistor is cut off is also larger, so that the time required for cutting off the driving transistor is further increased.
For the above reasons, the threshold voltage detection of the driving transistor can only be performed during the shutdown process, but cannot be performed during the startup process, that is, the threshold voltage of the driving transistor cannot be detected and compensated in real time during the display process, so that the luminance compensation effect of the display device is reduced, and the luminance of the display image is not uniform. In addition, the threshold voltage detection of the driving transistor is performed in the shutdown process, which also causes that the display device cannot be normally powered off after shutdown, so that the user experience is poor. Further, since, when performing luminance compensation for a display device, attention is generally paid only to detecting the threshold voltage of the driving transistor and performing luminance compensation calculation based only on the threshold voltage of the driving transistor, the luminance compensation effect of the display device tends to be limited.
At least one embodiment of the present disclosure provides a driving method of a pixel circuit. The pixel circuit includes a driving circuit, and the driving circuit includes a control terminal, a first terminal and a second terminal, the first terminal of the driving circuit is configured to be electrically connected to the sensing signal line and the light emitting element, and the second terminal of the driving circuit is configured to receive a power supply voltage. The driving method includes a blanking phase and a display phase. In a blanking stage, writing a first detection data voltage into a control end of a driving circuit to enable the driving circuit to be conducted, and detecting a first sensing voltage on a sensing signal line after the sensing signal line is charged for a first time through the driving circuit; writing a second detection data voltage into the control end of the driving circuit to enable the driving circuit to be conducted, and detecting the second sensing voltage on the sensing signal line after the sensing signal line is charged for a second time through the driving circuit, wherein the first detection data voltage is different from the second detection data voltage; and calculating characteristic parameters of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time and the second time. In the display phase, the display data voltage applied to the driving circuit is compensated based on the characteristic parameter.
The driving method can reduce the time required for detecting the threshold voltage of the driving circuit, thereby realizing real-time detection and real-time compensation of the driving circuit during startup, and also can obtain a plurality of characteristic parameters of the driving circuit including the threshold voltage, thereby achieving better display compensation effect based on the plurality of characteristic parameters and further improving the brightness uniformity of the display equipment.
At least one embodiment of the present disclosure also provides a compensation device and a display apparatus including the same to better compensate for a display data voltage applied to a pixel circuit, thereby achieving a better display effect of the display apparatus.
Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the same reference numerals in different figures will be used to refer to the same elements that have been described.
Fig. 1 is a flowchart of a driving method of a pixel circuit according to some embodiments of the present disclosure. The driving method can be used for detecting and calculating the characteristic parameters of the driving transistor of the pixel circuit in real time in the display process (namely, the process of displaying pictures, such as displaying static images or dynamic videos), without pausing or stopping the display process (namely, pausing or stopping the display pictures), thereby realizing the real-time compensation of the driving transistor. For example, the characteristic parameters may include a threshold voltage and a process constant of the driving transistor, and the driving method may compensate the display data voltage applied to the pixel circuit in real time based on the characteristic parameters, so as to achieve a better brightness compensation effect.
Fig. 2 is a schematic diagram of a pixel circuit 20 according to some embodiments of the present disclosure, and a driving method of the pixel circuit according to the embodiments of the present disclosure will be exemplarily described with reference to the pixel circuit 20 shown in fig. 2, but the embodiments of the present disclosure are not limited thereto.
For example, as shown in fig. 2, the pixel circuit 20 includes a driving circuit 100, and the driving circuit 100 includes a driving transistor T1. The gate of the driving transistor T1 serves as a control terminal of the driving circuit 100 and is configured to receive the data voltage; a first electrode (e.g., source electrode) of the driving transistor T1 is a first terminal of the driving circuit 100, and is electrically connected to the sensing signal line SEN and the light emitting element EL; a second pole (e.g., a drain) of the driving transistor T1 serves as a second terminal of the driving circuit 100, and is connected to the first power voltage terminal to receive the first power voltage Vdd.
For example, a data voltage Vdata, for example, may be applied to the gate of the driving transistor T1 through the data line DAT, and a reference voltage Vref, for example, may be applied to the first pole of the driving transistor T1 through the sensing signal line SEN, so as to control a voltage difference Vgs between the gate and the first pole of the driving transistor T1, that is, Vgs — Vdata-Vref, thereby controlling the on-state of the driving transistor T1 and the magnitude of the current flowing through the driving transistor T1.
For example, when Vgs > Vth (Vth is a threshold voltage of the driving transistor T1), the driving transistor T1 is in a turned-on state, so that the sensing signal line SEN (i.e., a capacitance or a parasitic capacitance connected thereto) can be charged by the current Ids output from the driving transistor T1. After the charging period, the value of the required sensing voltage may be obtained by detecting the voltage level on the sensing signal line SEN, and the characteristic parameters of the driving transistor T1 are calculated based on the obtained value, thereby compensating the display data voltage applied to the driving transistor T1.
For example, in a display process, one frame time includes a display phase and a blanking phase disposed between adjacent display phases. Each display stage is used for displaying a frame of image, and the time length of each display stage is equal to the time from the display of the first pixel point of the frame of image to the display of the last pixel point of the frame of image.
For example, as shown in conjunction with fig. 1 and 2, the driving method of the pixel circuit 20 may include a blanking phase and a display phase.
In a blanking phase, the driving method comprises the following steps:
step S10: writing a first detection data voltage into a grid electrode of the driving transistor to enable the driving transistor to be conducted, and detecting a first sensing voltage on the sensing signal line after the sensing signal line is charged for a first time through the driving transistor;
step S20: writing a second detection data voltage into the grid electrode of the driving transistor to enable the driving transistor to be conducted, and detecting a second sensing voltage on the sensing signal line after the sensing signal line is charged for a second time through the driving transistor;
step S30: and calculating the characteristic parameters of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time and the second time.
And, in the display phase, the driving method includes:
step S40: the display data voltage applied to the driving transistor is compensated based on the characteristic parameter.
For example, the first and second sensed data voltages Vt1 and Vt2 are not the same.
For example, the value of the first sensing voltage V1 and the value of the second sensing voltage V2 are not the same.
For example, the first time S1 and the second time S2 may be set as needed, for example, the first time S1 and the second time S2 may be the same or different. For example, the steps S10 and S20 may be performed continuously in the same blanking period, and the first time S1 and the second time S2 may be set to be 300 μ S to 350 μ S, for example, so as to greatly shorten the charging time of the sensing signal line SEN, so that the detection process of the characteristic parameter of the driving circuit 100 may be completed in the blanking period during the power-on period, thereby achieving the technical effect of real-time detection. For example, the steps S10 and S20 may also be performed in different blanking periods, respectively, the first time S1 and the second time S2 may be set to be 300 μ S to 500 μ S, for example, and the detection process of the characteristic parameter of the driving circuit 100 may also be completed in the blanking period during the power-on period, which is not limited in this disclosure.
For example, the driving method provided in some embodiments of the present disclosure is exemplified by the steps S10 and S20 being performed continuously in the same blanking period, so that errors caused by factors such as electron mobility variation can be avoided, and the accuracy of the detection result can be further improved.
For example, when the detected values of the first sensing voltage V1 and the second sensing voltage V2 are between 1V and 2V, the obtained detection result can be more accurate. Therefore, in steps S10 and S20, the first sensing voltage V1 and the second sensing voltage V2 can be within a range of 1-2V by adjusting the first sensing data voltage Vt1, the second sensing data voltage Vt2, the first time S1 and the second time S2, so that the calculated characteristic parameters of the driving circuit 100 are more accurate, and the display device including the pixel circuit 20 achieves a better compensation effect.
For example, in step S30, the calculated characteristic parameters of the driving circuit 100 include the threshold voltage Vth of the driving transistor T1, the process constant K of the driving transistor T1, and the like, and further, the luminance of the pixel circuit 20 can be compensated based on the characteristic parameters of the driving transistor T1, so that the display device including the pixel circuit 20 achieves a better compensation effect, and the luminance uniformity of the display screen is further improved.
The detection process of the characteristic parameter of the driving circuit 100 and the compensation method in conjunction with the characteristic parameter will be described in detail below.
As shown in fig. 2, the pixel circuit 20 may further include a data writing circuit 200, a sensing circuit 300, and a storage circuit 400.
For example, the data writing circuit 200 includes a data writing transistor T2, a gate of the data writing transistor T2 is connected to the scan line to receive the scan signal G1, a first pole of the data writing transistor T2 is connected to the gate of the driving transistor T1, and a second pole of the data writing transistor T2 is connected to the data line DAT. For example, under the control of the scan signal G1, when the data write transistor T2 is turned on, a data voltage (e.g., the first and second sensed data voltages Vt1 and Vt2 provided in a blank phase; a display data voltage provided in a display phase) supplied from the data line DAT may be written to the gate of the driving transistor T1 through the data write transistor T2, and the data voltage is stored by the memory circuit 400 as described below. For example, when the data write transistor T2 is turned off, subsequent steps such as charging the sense signal line SEN and detecting the voltage on the sense signal line SEN may be performed.
For example, the sensing circuit 300 includes a sensing transistor T3, a gate of the sensing transistor T3 is connected to the sensing signal control line to receive the sensing control signal G2, a first pole of the sensing transistor T3 is connected to the sensing signal line SEN, and a second pole of the sensing transistor T3 is connected to the first pole of the driving transistor T1 and the light emitting element EL.
For example, as shown in fig. 2, the sensing signal line SEN may be electrically connected to the reference voltage terminal through the first switching element SW1, and electrically connected to the detection circuit 500 through the second switching element SW 2.
For example, in the case where the sensing transistor T3 is turned on, when the first switching element SW1 is turned on and the second switching element SW2 is turned off, the reference voltage Vref provided from the reference voltage terminal is written to the first pole of the driving transistor T1 via the sensing signal line SEN and the sensing transistor T3 in sequence.
For example, in the case where the sensing transistor T3 is turned on, when the first switching element SW1 is turned off and the second switching element SW2 is turned on, the current Ids output by the driving transistor T1 may be transmitted to the sensing signal line SEN via the sensing transistor T3, thereby charging the sensing signal line SEN.
For example, with the sense transistor T3 turned off, when the first switching element SW1 is turned off and the second switching element SW2 is turned on, the voltage on the sense signal line SEN, for example, the first sense voltage V1 and the second sense voltage V2, may be detected by the detection circuit 500.
For example, the first switching element SW1 and the second switching element SW2 may be transistors, and may be other types of switching elements as long as the first switching element SW1 and the second switching element SW2 can achieve both off and on states. The detection circuit 500 may be implemented in various suitable forms, for example, and may include an amplification sub-circuit that amplifies the voltage detected from the sense signal line SEN to obtain an amplified voltage signal, an analog-to-digital conversion (ACD) circuit, and the like, which is converted by the analog-to-digital conversion circuit to a digital signal that may be used for subsequent analysis, calculation, and the like.
For example, as shown in FIG. 2, the storage circuit 400 includes a storage capacitor C1. A first terminal of the storage capacitor C1 is electrically connected to the first pole of the driving transistor T1 and the light emitting element EL, a second terminal of the storage capacitor C1 is electrically connected to the gate of the driving transistor T1 and the first pole of the data writing transistor T2, and the storage capacitor C1 is configured to store data voltages, such as a first sensed data voltage Vt1 and a second sensed data voltage Vt2, written through the data writing transistor T2. For example, when the data writing transistor T2 is turned off, and the driving transistor T1 is turned on under the control of the data voltage (e.g., the first sensed data voltage Vt1 and the second sensed data voltage Vt2) stored in the storage capacitor C1 to charge the sense signal line SEN, due to the capacitive coupling effect of the storage capacitor C1, as the voltage of the first electrode of the driving transistor T1 rises, the voltage of the gate electrode of the driving transistor T1 also rises, so that the Vgs of the voltage difference between the gate electrode and the first electrode of the driving transistor T1 is kept constant. Therefore, during the process of charging the sensing signal line SEN, the magnitude of the current Ids output by the driving transistor T1 is kept unchanged, and the voltage on the sensing signal line SEN rises linearly, so that the characteristic parameters of the driving circuit 100 can be calculated in the subsequent steps, and meanwhile, the charging speed of the sensing signal line SEN is increased, and the charging time is shortened.
Fig. 3 is a signal timing diagram of the pixel circuit 20 shown in fig. 2. For example, one or more lines (two or three lines) of light emitting elements may be detected in real time by the pixel circuit 20 in each blanking period, whereby the detection result may be used for real-time compensation.
For example, each blanking phase may include a first sensing data writing sub-phase t1, a first charging sub-phase t2, a first sensing sub-phase t3, a second sensing data writing sub-phase t4, a second charging sub-phase t5, and a second sensing sub-phase t 6. Step S10 may be implemented in the first sensing data writing sub-phase t1, the first charging sub-phase t2 and the first sensing sub-phase t3, and step S20 may be implemented in the second sensing data writing sub-phase t4, the second charging sub-phase t5 and the second sensing sub-phase t 6. Some embodiments of the present disclosure will be described below by taking the driving transistor T1, the data writing transistor T2, and the sensing transistor T3 as N-type transistors as an example in conjunction with the signal timing diagram shown in fig. 3. However, embodiments of the present disclosure are not limited thereto, and any one of the driving transistor T1, the data writing transistor T2, and the sensing transistor T3 may also be a P-type transistor.
For example, as shown in connection with fig. 3, step S10 may include:
step S110: in the first test data writing sub-phase t1, the data writing circuit 200 and the sensing circuit 300 are controlled to be turned on, the data writing circuit 200 writes the first test data voltage Vt1 to the control terminal of the driving circuit 100, and the sensing circuit 300 writes the first reference voltage Vref1 to the first terminal of the driving circuit 100.
For example, in step S110, the data writing transistor T2 is turned on in response to the scan signal G1 of high level, the sensing transistor T3 is turned on in response to the sensing control signal G2 of high level, the first switching element SW1 is turned on, the second switching element SW2 is turned off, the first sensed data voltage Vt1 is written to the gate of the driving transistor T1 through the data writing transistor T2, and the first reference voltage Vref1 provided from the reference voltage terminal is written to the source of the driving transistor T1 through the sensing transistor T3, so that the voltage difference Vgs between the gate and the source of the driving transistor T1 is: vgs is Vt1-Vref 1.
For example, in order to turn on the driving transistor T1, the first sensed data voltage Vt1, the first reference voltage Vref1 and the threshold voltage Vth of the driving transistor T1 should satisfy: vt1-Vref1 is equal to or greater than Vth. For example, to facilitate subsequent calculations, the first reference voltage Vref1 may be set to 0V.
For example, as shown in connection with fig. 3, step S10 may include:
step S120: in the first charging sub-phase t2, the data writing circuit 200 is turned off, the sensing circuit 300 is turned on, and the sensing signal line SEN is charged for a first time S1 by the driving circuit 100 and the sensing circuit 300 under the control of the first detected data voltage Vt 1.
For example, in step S120, the data writing transistor T2 is turned off in response to the scan signal G1 of a low level, the sensing transistor T3 is turned on in response to the sensing control signal G2 of a high level, the first switching element SW1 is turned off, the second switching element SW2 is turned on, the driving transistor T1 is turned on, and a first charging current Ids1 is generated and output, the first charging current Ids1 charges the sensing signal line SEN, for example, for a first time S1, via the sensing transistor T3.
For example, the duration of the first charging sub-phase t2 may be the same as the duration of the first time S1, but is not limited thereto, and the duration of the first charging sub-phase t2 may also be greater than the duration of the first time S1.
For example, due to the capacitive coupling effect of the storage capacitor C1, the voltage difference Vgs between the gate and the source of the driving transistor T1 is kept constant, i.e., Vgs is equal to Vt1-Vref1, during the first charging sub-phase T2, so that the first charging current Ids1 can be kept constant, and thus the voltage value on the sensing signal line SEN is linearly increased with time during the first charging sub-phase T2 as shown in fig. 3.
For example, in the first charging sub-phase T2, the driving transistor T1 is turned on and in a saturated state, the first charging current Ids1 can be obtained according to a current formula that the driving transistor T1 is in a saturated state, and the first charging current Ids1 is expressed as:
Ids1=K(Vt1-Vref1-Vth)2(1)
where K is a process constant of the driving transistor T1.
For example, as shown in connection with fig. 3, step S10 may include:
step S130: in the first detecting sub-phase t3, the data writing circuit 200 is controlled to be turned off, and after the sensing signal line SEN is charged for the first time S1, the sensing circuit 300 is controlled to be turned off, and the first sensing voltage V1 on the sensing signal line SEN is detected.
For example, in step S130, the data writing transistor T2 is turned off in response to the scan signal G1 of a low level, the sensing transistor T3 is turned off in response to the sensing control signal G2 of a low level, the first switching element SW1 is turned off, and the second switching element SW2 is turned on, so that the first sensing voltage V1 on the sensing signal line SEN may be detected by the detection circuit 500.
For example, the first sensing voltage V1 satisfies the following relation:
Ids1·S1=V1·C (2)
where C is a capacitance value of a capacitor connected to the sensing signal line SEN, and the capacitance value C may be a constant. The capacitance may be a parasitic capacitance between the sensing signal line SEN and the remaining signal lines and/or electrodes in the display device, or may be a capacitance separately provided at the sensing signal line SEN.
For example, as shown in connection with fig. 3, step S20 may include:
step S210: in the second test data writing sub-phase t4, the data writing circuit 200 and the sensing circuit 300 are controlled to be turned on, the data writing circuit 200 writes the second test data voltage Vt2 to the control terminal of the driving circuit 100, and the sensing circuit 300 writes the second reference voltage Vref2 to the first terminal of the driving circuit 100.
Step S210 is similar to step S110, and is not described herein again. It should be noted that, in order to turn on the driving transistor T1, the second detected data voltage Vt2, the second reference voltage Vref2 and the threshold voltage Vth of the driving transistor T1 should satisfy: vt2-Vref2 is equal to or greater than Vth. For example, the first reference voltage Vref1 and the second reference voltage Vref2 may be the same or different. For example, the second reference voltage Vref2 may also be set to 0V for the convenience of subsequent calculations.
For example, as shown in connection with fig. 3, step S20 may include:
step S220: in the second charging sub-phase t5, the data writing circuit 200 is controlled to be turned off, the sensing circuit 300 is controlled to be turned on, and the sensing signal line SEN is charged for a second time S2 through the driving circuit 100 and the sensing circuit 300 under the control of the second sensing data voltage Vt 2.
Step S220 is similar to step S120, and is not described herein again. Similarly, in step S220, in the second charging sub-phase T5, the driving transistor T1 is turned on and in saturation, the second charging current Ids2 can be obtained according to the current formula that the driving transistor T1 is in saturation, and the second charging current Ids2 is expressed as:
Ids2=K(Vt2-Vref2-Vth)2(3)
where K is a process constant of the driving transistor T1.
For example, in the second charging sub-phase t5, the second charging current Ids2 also remains unchanged, so that the voltage value on the sensing signal line SEN also increases linearly with time in the second charging sub-phase t5, as shown in fig. 3.
For example, the duration of the second charging sub-phase t5 may be the same as the duration of the second time S2, but is not limited thereto, and the duration of the second charging sub-phase t5 may also be greater than the duration of the second time S2.
For example, as shown in connection with fig. 3, step S20 may include:
step S230: in the second detection sub-phase t6, the data writing circuit 200 is controlled to be turned off, and after the sensing signal line SEN is charged for the second time S2, the sensing circuit 300 is controlled to be turned off, and the second sensing voltage V2 on the sensing signal line SEN is detected.
Step S230 is similar to step S130, and is not described herein again. In step S230, the second sensing voltage V2 satisfies the following relation:
Ids2·S2=V2·C (4)
where C is the capacitance value of the capacitance to which the sense signal line SEN is connected.
For example, as shown in FIG. 3, the first test sub-phase t3 and the second test data writing sub-phase t4 are immediately adjacent in time, i.e., the second test data writing sub-phase t4 is entered immediately after the first test sub-phase t3 ends; however, the embodiments of the present disclosure are not limited thereto, and a certain time may be spaced between the first sensing sub-phase t3 and the second sensing data writing sub-phase t 4.
For example, the duration of the first sensing data writing sub-phase t1 and the duration of the second sensing data writing sub-phase t4 may be the same; the duration of the first detection sub-phase t3 and the duration of the second detection sub-phase t6 may also be the same.
Thus, in step S30, from the above-described relational expressions (1) to (4), it can be derived that the value of the process constant K of the driving transistor T1 is:
the magnitude of the process constant K is related to the electron mobility of the driving transistor T1, i.e.: k is W/L × Cs × μ, where W/L is a width-to-length ratio (i.e., a ratio of width to length) of a channel of the driving transistor T1, μ is electron mobility, and Cs is capacitance per unit area, and therefore, the driving method provided by the embodiment of the disclosure can compensate the process constant K, so as to compensate for a difference of the driving transistor T1 caused by the electron mobility, and further improve uniformity of display luminance.
Meanwhile, it can also be derived from the above relations (1) to (4) that the value of the threshold voltage Vth of the driving transistor T1 is:
in step S40, the display data voltage applied to the driving transistor T1 may be compensated based on the above-described characteristic parameters, i.e., the threshold voltage Vth of the driving transistor T1 and the process constant K of the driving transistor T1. For example, step S40 may include: obtaining a display brightness value L according to the display gray scale; according to the characteristic parameter and the display luminance value L, a compensated data voltage Vdata1 corresponding to the display gray scale is obtained, and the compensated data voltage Vdata1 can be used as a display data voltage for driving the circuit 100 to perform the display operation.
For example, during the lighting of the OLED, the display brightness value of the OLED is proportional to the driving current flowing into the OLED, and the relationship between the display brightness value and the driving current is expressed as:
Ids=a·L,
wherein Ids is the driving current, L is the display luminance value, and a is a constant. L may be a normalized luminance value, i.e., 0 ≦ L ≦ 1, and when L is 1, the OLED displays luminance corresponding to a 255 gray scale, and when L is 0, the OLED displays luminance corresponding to a 0 gray scale.
For example, the compensated data voltage Vdata1 may be obtained by the following calculation formula according to the correspondence between the display luminance value L and the driving current Ids during the lighting of the OLED, that is:
where K is a process constant of the driving transistor T1, and Vth is a threshold voltage of the driving transistor T1. The compensated data voltage Vdata1 represents a display data voltage that has compensated for the threshold voltage Vth of the driving transistor T1 and the process constant K. Therefore, the display device is driven to display according to the compensated data voltage, so that the brightness uniformity of the display device can be improved, and the display effect of the picture is obviously improved. Therefore, the pixel circuit 20 can achieve better display compensation effect based on the characteristic parameters, and the brightness uniformity of the display device including the pixel circuit 20 is further improved.
For example, some embodiments of the present disclosure provide driving methods that may be performed during the blanking phase of each frame; alternatively, the driving method provided by other embodiments of the present disclosure may also be performed in the blanking period of the odd frame or the even frame; alternatively, the driving method provided by some embodiments of the present disclosure may also be performed in the blanking period of every other multiple frames, for example, in the blanking period of the (3N +1) th frame, where N is an integer greater than or equal to 0.
It should be noted that, although the above embodiment of the present disclosure only uses the pixel circuit 20 as the 3T1C circuit as an example to describe the driving method of the pixel circuit provided in the embodiment of the present disclosure, the pixel circuit 20 in other embodiments of the present disclosure is not limited to the 3T1C circuit, for example, the pixel circuit 20 may also be 4T1C, 4T2C, 6T1C and other pixel circuits having functions of electrical compensation and the like according to specific application requirements, and details are not repeated herein.
It should be noted that, in the pixel circuit 20 shown in fig. 2, the light emitting element EL may be, for example, various types of Organic Light Emitting Diodes (OLEDs), such as top emission, bottom emission, double-side emission, and the like, and the embodiment of the disclosure does not limit this. As shown in fig. 2, the anode of the exemplary OLED is electrically connected to a first pole of the driving transistor T1, and the cathode receives a second power supply voltage Vss, which is lower than the first power supply voltage Vdd. The light emitting element EL may be, for example, a quantum dot light emitting diode (QLED) or the like, which is not limited in the embodiment of the present disclosure.
For example, the light emitting element EL may emit red light, green light, blue light, white light, or the like, and in the case that the light emitting element EL displays light of different colors, the corresponding first time S1 and second time S2 may be the same or different, and the embodiment of the disclosure does not limit this.
For example, in the pixel circuit 20 shown in fig. 2, the driver circuit 100, the data writing circuit 200, the sensing circuit 300, and the memory circuit 400 may be circuits composed of other components.
For example, the driving transistor T1, the data writing transistor T2, and the sensing transistor T3 may all be N-type transistors or all be P-type transistors, or some transistors may be N-type transistors and some transistors may be P-type transistors. It should be noted that the transistors used in the embodiments of the present disclosure may be thin film transistors, field effect transistors, or other switching devices with the same characteristics. The source and drain of the transistor used herein may be symmetrical in structure, so that there may be no difference in physical structure between the source and drain. In the embodiments of the present disclosure, in order to distinguish the other two poles of the transistor except for the gate serving as the control terminal, one pole is directly described as the first pole, and the other pole is directly described as the second pole, so that the first pole and the second pole of all or part of the transistors in the embodiments of the present disclosure may be interchanged as necessary. For example, a first pole of a transistor of an embodiment of the present disclosure may be a source, and a second pole may be a drain; alternatively, the first pole of the transistor is the drain and the second pole is the source.
It should be noted that other essential steps of the driving method of the pixel circuit can refer to the conventional driving method of the pixel circuit, and are not described herein again.
At least one embodiment of the present disclosure also provides a compensation device, and fig. 4 is a schematic block diagram of a compensation device 50 provided in some embodiments of the present disclosure.
As shown in fig. 4, the compensation apparatus 50 includes a data driving circuit 510, a voltage detecting circuit 520, a calculating circuit 530, and a compensating circuit 540.
For example, the compensation device 50 is electrically connected to the pixel circuit 60, the pixel circuit 60 includes a driving circuit 600, the driving circuit 600 includes a control terminal 630, a first terminal 610 and a second terminal 620, the first terminal 610 of the driving circuit 600 is configured to be electrically connected to the sensing signal line SEN and the light emitting element EL, the second terminal 620 of the driving circuit 600 is configured to receive the first power voltage Vdd, and each frame time includes a blanking period and a display period.
For example, the data driving circuit 510 is configured to sequentially write the first detection data voltage and the second detection data voltage to the control terminal 630 of the driving circuit 600 in the blank period.
For example, the first detection data voltage and the second detection data voltage may be preset by a user, or may be automatically generated by the compensation device 50.
For example, the data driving circuit 510 may be implemented as a semiconductor chip.
For example, the voltage detection circuit 520 is configured to, during the blanking phase: the first sensing voltage on the sensing signal line SEN is detected after the sensing signal line SEN is charged for a first time by the driving circuit 600 under the control of the first sensing data voltage, and the second sensing voltage on the sensing signal line SEN is detected after the sensing signal line SEN is charged for a second time by the driving circuit 600 under the control of the second sensing data voltage.
For example, the voltage detection circuit 520 includes the detection circuit 500 shown in fig. 2. The voltage detection circuit 520 may be implemented in various suitable forms, and may include, for example, an amplification sub-circuit that amplifies the voltage detected from the sense signal line SEN to obtain an amplified voltage signal, an analog-to-digital conversion (ACD) circuit, and the like, which is converted by the analog-to-digital conversion circuit to a digital signal that may be used for subsequent analysis, calculation, and the like.
For example, the calculation circuit 530 is configured to calculate the characteristic parameter of the driving circuit 600 according to the first detected data voltage, the second detected data voltage, the first sensing voltage, the second sensing voltage, the first time, and the second time in the blanking period.
For example, the calculation circuit 530 may be formed using elements such as a transistor, a resistor, a capacitor, and an amplifier. For another example, the calculation circuit 530 may be implemented by a signal processor such as an FPGA, a DSP, or an MCU. The calculation circuit 530 may also include, for example, a processor and a memory, the processor executing a software program stored in the memory to implement a function of calculating the characteristic parameter of the drive circuit 600 from the first detected data voltage, the second detected data voltage, the first sensed voltage, the second sensed voltage, the first time, and the second time.
For example, the compensation circuit 540 is configured to compensate the display data voltage applied to the driving circuit 600 based on the characteristic parameter during the display phase.
For example, the compensation circuit 540 may include a processor and a memory, for example, the processor executes a software program stored in the memory to implement a function of compensating the display data voltage applied to the driving circuit 600 based on the characteristic parameter in the display phase, for example, including calculating a compensated data voltage corresponding to the display gray scale according to the characteristic parameter and the display luminance value obtained from the display gray scale, and the compensated data voltage may be used as the display data voltage for the driving circuit 600 to perform the display operation.
It should be noted that, regarding the operation performed by the compensation circuit 540, reference may be made to the above-mentioned related description of step S40 of the driving method shown in fig. 1, and details are not repeated here.
At least one embodiment of the present disclosure further provides a display device including the compensation apparatus according to any one of the embodiments of the present disclosure.
For example, at least one embodiment of the present disclosure provides a display device further including a display panel, wherein the display panel includes a plurality of pixel units, each pixel unit includes a pixel circuit, and the compensation device is configured to compensate for a driving circuit of the display panel.
For example, in a display device provided in at least one embodiment of the present disclosure, the pixel circuit further includes a data writing circuit, a storage circuit, and a sensing circuit, the data writing circuit includes a data writing transistor, the storage circuit includes a storage capacitor, the sensing circuit includes a sensing transistor, the driving circuit includes a driving transistor, a first electrode of the data writing transistor is electrically connected to the data line, a control electrode of the data writing transistor is electrically connected to the gate line, a second electrode of the data writing transistor is electrically connected to the first electrode of the storage capacitor and the control electrode of the driving transistor, a second electrode of the storage capacitor is electrically connected to the first electrode of the driving transistor, the second electrode of the driving transistor is electrically connected to the power supply voltage terminal to receive the power supply voltage, and the first electrode of the driving transistor is further electrically connected to the light emitting element and the first electrode of the sensing transistor, the second electrode of the sensing transistor is electrically connected to the sensing, the control electrode of the sensing transistor is electrically connected to the sensing control line.
For example, the display device may be any product or component having a display function, such as a liquid crystal panel, electronic paper, an OLED panel, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, and a navigator, and the embodiments of the disclosure are not limited thereto.
For example, when performing luminance compensation on the display device, first the characteristic parameters of the pixel circuits may be acquired line by line, and then, after the characteristic parameters of all the pixel circuits of the display device are acquired, a compensation amount may be established for each pixel circuit; finally, performing brightness compensation on the display device based on the established compensation amount; thereby, one-cycle brightness compensation can be completed. These compensation amounts may be saved, for example, in the form of a look-up table for easy recall or update.
For example, when acquiring the characteristic parameters of all the pixel circuits of the display device, the driving method of the pixel circuit provided in any one of the embodiments of the present disclosure may be first performed on the pixel circuit located in the first row, and the characteristic parameters of the pixel circuit located in the first row may be acquired; then, the driving method of the pixel circuit provided by any embodiment of the present disclosure may be performed on the pixel circuit located in the second row, and the characteristic parameter of the pixel circuit located in the second row is obtained; then, pixel circuits of the display device located in other rows can be detected line by line until characteristic parameters of all the pixel circuits of the display device are obtained; finally, a compensation amount is established for each pixel circuit, and luminance compensation is performed on the display device.
For example, when acquiring the characteristic parameters of all the pixel circuits of the display device, according to the practical application requirement, after the characteristic parameters of a row of pixel circuits are acquired by detection, a compensation amount may be established for each pixel circuit of the row, and then the pixel circuits located in the row are compensated for display brightness. For example, the current characteristic parameter calculation, the compensation amount establishment, and the display luminance compensation may be performed for the pixel circuits of the first row first, then the current characteristic parameter calculation, the compensation amount establishment, and the display luminance compensation may be performed for the pixel circuits of the fifth row, for example, and then the current characteristic parameter calculation, the compensation amount establishment, and the display luminance compensation may be performed for the pixel circuits of the second row, for example, until the characteristic parameter calculation, the compensation amount establishment, and the display luminance compensation are completed for all the pixel circuits included in the display device, whereby the display luminance compensation of one period may be implemented for the display device.
For the present disclosure, there are also the following points to be explained:
(1) the drawings of the embodiments of the disclosure only relate to the structures related to the embodiments of the disclosure, and other structures can refer to the common design.
(2) Thicknesses and dimensions of layers or structures may be exaggerated in the drawings used to describe embodiments of the present invention for clarity. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, it can be "directly on" or "under" the other element or intervening elements may be present.
(3) Without conflict, embodiments of the present disclosure and features of the embodiments may be combined with each other to arrive at new embodiments.
The above description is only for the specific embodiments of the present disclosure, but the scope of the present disclosure is not limited thereto, and the scope of the present disclosure should be subject to the scope of the claims.

Claims (13)

1. A driving method of a pixel circuit, wherein the pixel circuit comprises a driving circuit, the driving circuit comprises a control terminal, a first terminal and a second terminal, the first terminal of the driving circuit is configured to be electrically connected with a sensing signal line and a light emitting element, the second terminal of the driving circuit is configured to receive a power supply voltage,
the driving method comprises a blanking phase and a display phase,
in the blanking phase, it is possible to,
writing a first detection data voltage into the control terminal of the driving circuit to turn on the driving circuit, charging the sensing signal line for a first time through the driving circuit, and detecting a first sensing voltage on the sensing signal line,
writing a second detection data voltage into the control terminal of the driving circuit to turn on the driving circuit, and detecting a second sensing voltage on the sensing signal line after the sensing signal line is charged by the driving circuit for a second time, wherein the first detection data voltage is different from the second detection data voltage,
calculating a characteristic parameter of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time and the second time; and
in the display phase, the display data voltage applied to the driving circuit is compensated based on the characteristic parameter.
2. The driving method according to claim 1, wherein the pixel circuit further comprises a data writing circuit electrically connected to a control terminal of the driving circuit, the blanking phase comprises a first detection data writing sub-phase, a first charging sub-phase, a first detection sub-phase, a second detection data writing sub-phase, a second charging sub-phase, and a second detection sub-phase,
the driving method further includes:
in the first detection data writing sub-stage, controlling the data writing circuit to be conducted, and writing the first detection data voltage into the control end of the driving circuit through the data writing circuit;
in the first charging sub-phase, the data writing circuit is controlled to be switched off, and the sensing signal line is charged for the first time through the driving circuit under the control of the first detection data voltage;
in the first detection sub-phase, controlling the data writing circuit to be disconnected, and detecting the first sensing voltage on the sensing signal line after charging the sensing signal line for the first time;
in the second detection data writing sub-stage, controlling the data writing circuit to be conducted, and writing the second detection data voltage into the control end of the driving circuit through the data writing circuit;
in the second charging sub-phase, the data writing circuit is controlled to be switched off, and the sensing signal line is charged for the second time through the driving circuit under the control of the second detection data voltage;
and in the second detection sub-phase, the data writing circuit is controlled to be disconnected, and the second sensing voltage on the sensing signal line is detected after the sensing signal line is charged for the second time.
3. The driving method according to claim 2, wherein the pixel circuit further includes a sensing circuit, a first terminal of which is electrically connected to the sensing signal line, and a second terminal of which is electrically connected to the first terminal of the driving circuit and the light emitting element, wherein,
in the first detection data writing sub-phase, controlling the sensing circuit to be conducted, and writing a first reference voltage into the first end of the driving circuit through the sensing circuit;
in the first charging sub-phase, controlling the sensing circuit to be conducted so as to charge the sensing signal line for the first time;
in the first detection sub-phase, after the sensing signal line is charged for the first time, the sensing circuit is controlled to be closed, and the first sensing voltage on the sensing signal line is detected;
in the second detection data writing sub-phase, controlling the sensing circuit to be conducted, and writing a second reference voltage into the first end of the driving circuit through the sensing circuit;
in the second charging sub-phase, the sensing circuit is controlled to be conducted so as to charge the sensing signal line for the second time;
and in the second detection sub-phase, after the sensing signal line is charged for the second time, the sensing circuit is controlled to be closed, and the second sensing voltage on the sensing signal line is detected.
4. The driving method according to claim 3, wherein the pixel circuit further includes a memory circuit, first and second terminals of which are electrically connected to the control terminal and the first terminal of the driving circuit, respectively,
the storage circuit is configured to store the first detection data voltage and the second detection data voltage written by the data writing circuit.
5. The driving method according to claim 3, wherein, in the first charge sub-phase, a potential difference value between the control terminal and the first terminal of the driving circuit is kept constant;
in the second charging sub-phase, the potential difference value between the control terminal and the first terminal of the driving circuit is kept unchanged.
6. The driving method according to claim 1, wherein the first time is the same as the second time.
7. The driving method according to claim 3, wherein the driving circuit includes a driving transistor, the characteristic parameter includes a process constant and a threshold voltage of the driving transistor,
the threshold voltage is obtained by the following calculation formula:
wherein Vth is a threshold voltage of the driving transistor, Vt1 is the first test data voltage, Vt2 is the second test data voltage, V1 is the first sensing voltage, V2 is the second sensing voltage, Vref1 is the first reference voltage, Vref2 is the second reference voltage, S1 is the first time, S2 is the second time,
the process constant is obtained by the following calculation formula:
wherein K is a process constant of the driving transistor, and C is a capacitance value of a capacitor connected to the sensing signal line.
8. The driving method according to claim 7, wherein the first detection data voltage, the first reference voltage, and the threshold voltage of the driving transistor satisfy the following relation:
Vt1-Vref1≥Vth,
the second detection data voltage, the second reference voltage, and the threshold voltage of the driving transistor satisfy the following relation:
Vt2-Vref2≥Vth。
9. the driving method according to any one of claims 1 to 8, wherein compensating the display data voltage applied to the driving circuit based on the characteristic parameter includes:
obtaining a display brightness value according to the display gray scale;
and obtaining compensated data voltage corresponding to the display gray scale according to the characteristic parameters and the display brightness value, wherein the compensated data voltage is used as the display data voltage for the driving circuit to perform display operation.
10. A compensation device comprises a data driving circuit, a voltage detecting circuit, a calculating circuit and a compensation circuit,
wherein the compensation device is electrically connected with the pixel circuit, the pixel circuit comprises a driving circuit, the driving circuit comprises a control terminal, a first terminal and a second terminal, the first terminal of the driving circuit is configured to be electrically connected with the sensing signal line and the light-emitting element, the second terminal of the driving circuit is configured to receive a power supply voltage, each frame time comprises a blanking period and a display period,
the data driving circuit is configured to write a first detection data voltage and a second detection data voltage to the control terminal of the driving circuit in sequence in the blanking period;
the voltage detection circuit is configured to, during the blanking phase:
detecting a first sensing voltage on the sensing signal line after charging the sensing signal line for a first time by the driving circuit under the control of the first detection data voltage, an
Under the control of the second detection data voltage, after the sensing signal line is charged for a second time through the driving circuit, detecting a second sensing voltage on the sensing signal line;
the calculation circuit is configured to calculate a characteristic parameter of the driving circuit according to the first detection data voltage, the second detection data voltage, the first sensing voltage, the second sensing voltage, the first time, and the second time in the blanking period;
the compensation circuit is configured to compensate the display data voltage applied to the driving circuit based on the characteristic parameter during the display phase.
11. A display device comprising the compensation arrangement of claim 10.
12. The display device of claim 11, further comprising a display panel,
wherein the display panel comprises a plurality of pixel units, each pixel unit comprises the pixel circuit, and the compensation device is configured to compensate the driving circuit of the display panel.
13. The display device according to claim 11 or 12, wherein the pixel circuit further comprises a data writing circuit, a storage circuit, and a sensing circuit,
the data write circuit includes a data write transistor, the storage circuit includes a storage capacitor, the sense circuit includes a sense transistor, the drive circuit includes a drive transistor,
a first electrode of the data writing transistor is electrically connected to a data line, a control electrode of the data writing transistor is electrically connected to a gate line, a second electrode of the data writing transistor is electrically connected to a first electrode of the storage capacitor and a control electrode of the driving transistor,
the second pole of the storage capacitor is electrically connected to the first pole of the driving transistor,
the second electrode of the driving transistor is electrically connected to a power voltage terminal to receive a power voltage, and the first electrode of the driving transistor is further electrically connected to the light emitting element and the first electrode of the sensing transistor,
the second pole of the sensing transistor is electrically connected with the sensing signal line, and the control pole of the sensing transistor is electrically connected with the sensing control line.
CN201910273161.0A 2019-04-04 2019-04-04 Driving method of pixel circuit, compensation device and display equipment Pending CN111785195A (en)

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WO2013066017A1 (en) * 2011-10-30 2013-05-10 Yong Man Lee Display and touch panels with drive and sense techniques
KR102081132B1 (en) * 2013-12-30 2020-02-25 엘지디스플레이 주식회사 Organic Light Emitting Display
KR102122542B1 (en) * 2014-07-10 2020-06-29 엘지디스플레이 주식회사 Organic Light Emitting Display Device
KR20160050158A (en) * 2014-10-28 2016-05-11 삼성디스플레이 주식회사 Scan sense driver and display device including the same
KR20170003247A (en) * 2015-06-30 2017-01-09 엘지디스플레이 주식회사 Device And Method For Sensing Threshold Voltage Of Driving TFT included in Organic Light Emitting Display
KR20170024187A (en) * 2015-08-24 2017-03-07 삼성디스플레이 주식회사 Pixel and organic light emitting display device having the same
CN105609029B (en) * 2016-03-24 2019-10-01 深圳市华星光电技术有限公司 Sense the system and AMOLED display device of AMOLED pixel driver characteristic
CN107909965B (en) * 2017-12-07 2019-08-13 京东方科技集团股份有限公司 Compensation method and device for display panel

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